Compression propeller



July 27, 1937. H. L. ADAMS COMPRESSION PROPELLER 2 Sheets-Sheet 1 FiledNOV. 22, 1932 July 27, 1937. ADAMS 2,088,255

GOMPRESS ION PROPELLER Filed Nov. 22, 1932 2 Sheets-Sheet?-'{IIIIIIIII/I/ m'mm wm Patented July 27, 1937 UNITED STATES PATENTOFFICE 2,088,255 COMPRESSION PROPELLER Herbert Luther Adams, Washington,D. 0. Application November 22, 1932, Serial No. 644,560

16 Claims.

This invention relates to propellers for flying machines, and theapplication is a continuation in part of my prior application SerialNumber 461,412, filed April 14, 192-1, and since maturing into PatentNo. 1,888,418.

One of the main objects is to provide a variable propeller that may beutilized at a low pitch to' givegreater tractive force when startingupon the ground and may be changed to a much higher pitch andgreaterlength of blades as the altitude of the aeroplane above theground is increased .to a point where the air has become more rare andin that way greatly increasing the efliciency of the propeller.

Another object is to provide auxiliary propellers which have a steepinclination of the entering edge to draw the air out of the dead centerand to derive tractive force therefrom and to destroy parasiteresistance on the main engine and fuselage thereby.

A still further object is to'provide a means for varying the angle ofattack upon the dead center of air in the path of the. main propeller sothat with rarefied air the same efliciency may be obtained by theauxiliary propeller as in the more dense atmosphere.

A still further object is to provide a. main propeller with substantialincreasable length of blades in the more rarefied air or when conditionsrequire to increase the area of attack and to give a greater tractiveforce.

A still further object is to provide a propeller control device that maybe operated manually through a power force to control the pitch of thepropeller or it may be operated automatically by atmospheric pressureresponsive device associated was obtained with the pitch controlmechanism to relieve the, operator from paying attention to this detailof changing the pitch of propeller.

To these ends my invention consists in certain novel features, which Iwill now proceed to describe and will then particularly point out in theclaims. a

Figure 1 is a front view of variable pitch adjustable propeller with anadjustable auxiliary propeller in accordance with this invention.

Figure 2 is a plan view of the propeller shown in Figure 1 with adiagrammatic view of the starter of the propeller.

Figure 3 is a longitudinal sectional view through the main crank shaftof the engine showing the method of varying the pitch and length oi. thepropeller shown in Figure 1.

Figure 4 is a section taken on the line 4-4 of Figure 3.

Figure 5 is a section taken on the line 5-5 of Figure 3. I 1

Figure 6 is a section of the rear end of the crank shaft taken on theline 6-6 of Figure 3'.

Figure 7 is a'fragmentary longitudinal section 5 of a modified-form ofpropeller.

Figure 8 is a fragmentary section through another modified form ofpropeller.

Figure 9 is a cross section through the hub of propeller, a modificationof Figure 3.

Figure 10 is a diagrammatic view of the propeller showing the effect ofthe auxiliary propeller in forcing the air from the central part andcompressing near the outer rim to give greater tractive force and reduceparasitic resistance or friction to the onrushing fuselage.

Referring to the drawings, in detail, the numeral I indicates a pair ofpropeller blades which project from lateral extensions of a hubstructure formed of a pair of separable sections 2 and 3 disposedtransversely of the crank shaft or propeller shaft 12, and securedtogether by some suitable means such as the split collars 33 and bolts34. Although two blades and two hub extensions are shown, any numberdesired may be employed.

Each of the hub extensions is of hollow construction, and is-providedwith a transverse'partition l which divides the interior of theextension into an inner portion comprising a pressure chamber or pistonchamber 6, and an outer portion adapted to receive therein the inner endportion 8 of a propeller blade I. This portion 8 of the propeller bladehas its peripheral faceformed with diagonal grooves 9 which slidablyreceive therein pins l0 projecting radially from the'inner face of thehollow extension receiving the blades. A piston 5 is slidably mountedwithin the chamber 6, and is connected with the portion 8 of the blade Iby means of a pistonrod l which 40 slidably extends through thepartition 1. The crank shaft or propeller shaft |2 is of hollowconstruction, and the interior thereof is connected with the chambers 6of the hub structure by means of fluid conducting pipes l I which openinto the chambers 6 adjacent the partitions 1. The interior of the crankshaft is adapted to have a compressed fluid conducted therethrough tothe parts or pipes H, such fluid entering the crank shaft through athrust connection l3 extending into the rear end of the crank shaftthrough a suitable fluid tight bearing in a head I8 mounted on said rearend. The thrust connection l3 receives the fluid through a hollowpressure arm I! having a pipe connection IS with a suitable source offluid pressure supply, not shown. The pressure arm I4 is pivotallymounted adjacent its center as indicated at l6, and is provided with apressure adjusting rod II in threaded engagement with some suitablerigid element such as the rear bearing support for the crank shaft l2.

The head I8 is preferably formed with an annular chamber 26 which isconnected by means of a pipe IS with the source of fluid pressuresupply. Opening into the chamber is a fluid conducting pipe 2| whichextends into and through the hollow interior of the crank shaft, andalso partially through the hub structure to a pressure chamber or pistonchamber 22 formed in the forward face of the hub structure, andextending axially thereof in alignment with the foremost portion of thecrank shaft. Slidably mounted within the chamber 22 is a piston 23having a piston rod 24 projecting forwardly from the hub structure. Thepiston rod 24 is pivotally connected by means of a bolt or pin 25 with apair of links 26 which are also pivotally connected respectively bymeans of bolts or pins 21 with a pair of auxiliary propeller blades 26.Although two of the auxiliary propeller blades 28 are shown anddescribed, this number may be varied as desired.

Preferably the number of auxiliary blades will correspond to the numberof the main blades with the auxiliary blades preferably arranged in amanner to bisect the spaces between the main blades.

In order that external power may be applied to the'crank shaft to startthe motor of the flying machine, I provide a gear 29 fixedly mounted onthe crank shaft, and operatively connected by means of intermediategears 30, 30a and 30b with a gear 30c flxedly mounted on the crank shaft3| of a starting or auxiliary motor, a connectin'g rod or piston rod ofwhich is shown at 32.

In operation, fluid under pressure is admitted through the thrustconnection i3 to the interior of the crank shaft |2, from where it ispassed through the pipes H to the pressure chambers 6. The propellerblades I have a tendency to slide outwardly with respect to the hubstructure by the action of centrifugal force, and an appropriatepressure is maintained within the pressure chambers for coaction withthe pistons 5 to hold the blades in the desired position in accordancewith prevailing conditions, such as the altitude at which the machine isflying. When it is desired to increase the effective length of theblades,

the pressure within the chambers 6 is reduced to permit the pistons tobe drawn by centrifugal force toward the partitions I. Owing to theinclination of the grooves 9 having the pins I0 slidably receivedtherein, the pitch of the blades is automatically reduced or increasedwith the reduction or increase in the eifective length of the blades.

In order to relieve pressure on the inner faces of the pistons 5, and topermit the escape of any fluid that may seep past the pistons, eachchamber 6 is provided at its inner end with a vent 31 as shown in Figure3. This vent may also be in the nature of a tube 35, as shown in Figure9, and the ports or tubes 35 from the several chambers all extend to thepipe 36 for connection there similarly to pipe 2|. The other end of pipe36 is connected with separate opening similar to chamber 20 with vacuumor other connection similar to pipe IS.

The adjustment of the auxiliary blades 28 is accomplished independentlyof any adjustment of the main blades by means of fluid pressure which isadmitted to the pipe 2| through the pipe I! and chamber 20. Externalpressure on the auxiliary blades tends to force them apart toward theirmaximum arc of rotation, and when it is desired to reduce their are ofrotation, the internal pressure on the piston 23 is increased to drawthe blades 28 toward each other through the action of the rod 24 andlinks 26. Owing to therelatively low speed of the tips of the auxiliarypropellers in distance per second, as compared to the correspondingspeed of the tips of the main blades l, the pitch of the auxiliaryblades should be high at all times. The action of the auxiliary bladestend to force the air outwardly from the axial line of the hubstructure, thereby compressing the air to a certain extent within thepath of the main blades I, and thinning the air in the immediate path ofthe flying machine body to decrease air resistance on the latter.

In the embodiment of the invention shown in Figure 7, each of the hubextensions 33 is formed with a recess 39 to slidably receive an innerend portion of a propeller blade 40 therein. The inner portion of theblade and the wall of the recess 39 will be provided with any suitablemeans such as grooves and pins to maintain the proper angular positionof the blade with respect to the hub extension.

The inner end portion of the blade is of hollow construction to providea chamber 4| having a removable closure 42 at the inner end thereof.Slidably mounted within each chamber 4| is a piston 43 having a stem 44slidably extending through the closure 42 into the hub wherein it isrigidly anchored. The stem 44 is provided with' a lengthwise extendingbore 45, one end of which opens into the chamber 4| adjacent the innerface of the piston 43, and the other end of which opens into the hollowcrank shaft 46.

In operation, the blades 40 are normally urged outwardly by centrifugalforce whereby the inner end of the chamber 4| is moved toward thestationary piston 43. when it is desired to move the blades inwardly toshorten the eiIective length thereof, or to prevent further outwardmovement of the blades, fluid under pressure is admitted through thehollow crank shaft to the bore 45 for' expansion within the chamber 4|inwardly of the piston 43. A pressure relief vent 41 is provided for therecess 39, and a similar vent 46 is provided for the chamber 4| at theouter end of the latter. Both of these vents are open to the atmosphere.

In the embodiment of the invention shown in of the recess 53 and theinner end portion of the blade to maintain the latter in proper rotativeposition with respect to the extension. Slidably disposed within eachchamber 52 is a piston 55 which is connected with "the inner end of theadjacent blade 54 by means of a piston rod 56 slidably extendingthroughthe partition 5|.

chambers 52 adjacent the partitions slidably disposed within the hollowextension .49, which also forms a pressure chamber, is a piston 51having a piston rod 58 connecting the same with a diaphragm 59 disposedtransversely and forwardly of the extension 49. Opening into the rearportion of the hollow extension 49 are fluid conducting pipes 60 whichalso open into the Also opening into the rear portion of thehollowextension 43 is a bore Bl extending lengthwise of the propeller shaft 62and adapted to be connected in: any suitable manner with a source offluid pressure supply, not shown. The chambers 52 are provided at theirinner ends with pressure relief vents 63 which are open totheatmosphere.

- 'In use, the structure shown in Figure 8 may be operated manually orautomatically, as desired. In the manual operation of thesame,suflicient pressure is admitted through the bore GI and pipes 60 tothe chambers 52 to maintain the blades 54 in proper position inaccordance with prevailing conditions. In the rarer atmosphere, or atany time that it is desired to increase the effective length or thepitch of the blades, the pressure is reduced sufiiciently to enable theblades to move outwardly by the action of centrifugal force.

When it is desired to operate the device automatically, a predeterminedconstant pressure is maintained therein which is substantiallysufficient to hold the blades against the action of centrifugal force ina comparatively dense atmosphere; With such an adjustment, when higheraltitudes are reached. the external pressure on the diaphragm, and alsothe external'resistance to centrifugal movement of the blades, decreaseina corresponding degree, whereby the compressed fluid is graduallytransferred from the chambers 52, through the pipes 60 to the chamberwithin thehollow extension 49. When descending, as lower altitudes arereached, the external pressure on the diaphragm, and the externalresistance to centrifugal movement of the blades increase, and thecompressed fluid is retransferred from the hollow extension 49 to thechambers 52.

It is apparent that the basic principles of' this invention can be usedwith any type of engine including a radial engine without departing from.the spirit of the device.

The chamber 20 could be placed between the propeller and the engine byany one skilled in the art if desired without departing from the spiritof the invention. I

It is to be noted that the auxiliary propeller can be made. unadjustablewithout departing from the spirit of the invention and can be used withanytype of propeller.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is:

1. In a flying machine, a propeller shaft, a hub carried by said shaftand having lateral extensions, propeller blades extending into saidextensions and having slidable and rotatable connections therewith,means to provide pressure chambers within said extensions, pistonswithin said chambers, rods connecting said-pistons with said blades, andhydraulic means for moving said pistons.

2. In a flying machine, a propeller'shaft having a fluid pressureconduit, a hub carried by said shaft and having lateral extensions,propeller blades slidably and rotatably extending into saidextensionsfmeans to provide pressure chambers within said extensions,pistons in said chambers adapted to slide the blades upon theintroduction of fluid under pressure to the chambers, means to establishcommunication between said chambers and fluid pressure conduit foradmitting fluid under pressure to the chambers, having pressure reliefvents'for said chambers, and coacting means on said extensions andblades for rotating the blades upon sliding movement thereof.

3. In a flying-machine, a propeller shaft, a hub carried by said shaftand having lateral extensions, propeller blades slidably extending intosaid extensions, means to provide pressure chambers within saidextensions, pistons in said chambers adapted to slide the blades uponthe in-- troduction of fluid under pressure to the chambers, means forintroducing.fluid under pressure to said chambers, and having pressurerelief vents for saidchambers.

4. In a flying machine, a propeller shaft having a hub, a forwardextension and a plurality of lateral extensions on the hub, means withineach of said extensions to provide a pressure chamber, pistons slidablein said chambers, propeller blades slidably extending into said lateralextensions, piston rods connecting the blades with the pistons in thelateral extension pressure chambers, a diaphragm disposed crosswise ofsaid forward extension, a piston rod connecting the diaphragm \viththepiston in the forward exten sion pressure chamber, and having constantcommunication between all of said chambers.

5. In a flying machine, a ropeller shaft, propeller blades slidablymounted with respect to the shaft and extending laterally therefrom, adiaphragm'movable axially of said shaft, and

means operatively connecting the diaphragm with said blades wherebymovement of the diaphragm axially of the shaft causes sliding movementof said blades.

6. In a flying machine, a propeller shaft, radially movable propellerblades extending laterally from said shaft, a diaphragm movable axiallyof said shaft, and means operatively connecting the diaphragm with saidblades whereby movement of the diaphragm axially of the shaft causesradial movement of said blades.

7. In a flying machine, a propeller shaft, a hub carried by said shaftand having lateral extensions, propeller blades slidably extending intosaid extensions, having pressure chambers in inner end portions of saidblades, pistons slidably received within said. chambers, means foranchoring said pistons to said hub, and means to provide a fluidpressure conduit opening into said chamber.

8. In a flying machine, a propeller shaft having a fluid pressureconduit, a hub carried by said shaft and having lateral extensions,propeller blades slidably extending into said extensions,

. propeller blades exmnding laterally from and rotatable with saidshaft, auxiliary propeller blades forwardly of the main blades androtat.

able therewith and extending diagonally from said shaft at a forward andoutward inclination and extension, and means for adjusting said forwardand outward inclination and extension ofsaid auxiliary blades.

' 10. In a flying machine, a propeller shaft, main propeller bladesextending laterally from and rotatable with said shaft, and auxiliarypropeller blades forwardly of the main blades and rotatable therewithand extending diagonally from said shaft at a forward and outwardinclination and extension.

11. In a propeller, a shaft, elongating main propeller blades movable ina radial direction and attached to and rotatable with said shaft,auxiliary propeller blades forward of the main blades, said auxiliaryblades being attached at their bases by pivoted connections, the centerlines of said connections each being excentric, non-parallel andnon-intersecting to the center line of said shaft, direct acting meansto move said main propeller blades radially and controllable means toadjust said auxiliary blades about said pivoted connections while saidauxiliary blades are in use.

12. In a propeller, a shaft, elongating main propeller blades movable ina radial direction and attached to and rotatable with said shaft,auxiliary propeller blades forward of the main blades, said auxiliaryblades being attached to the base by pivoted connections and secured torotate with said shaft, the center lines of said connections each beingcapable of a tangential relation to a cylinder of suitable sizeconcentric with said shaft, and controllable means to adjust saidauxiliary blades about said pivoted connections while in use.

13. In a propeller, a shaft, elongating main propeller blades movablewith respect to said shaft in a radial direction and rotatable with saidshaft, auxiliary propeller blades forward of the main blades, saidauxiliary blades being attached to the shaft by pivoted connections, thecenter lines of said connections each being capable of a tangentialrelation to a cylinder of suitable size concentric with said shaft,direct acting means to adjust said main propeller blades radially andcontrollable means to adjust said auxiliary blades about said pivotedconnections.

14. In a propeller shaft, main propeller blades attached to said shaftand rotatable with said shaft, auxiliary propeller blades forward of themain blades, said auxiliary blades being attached to the shaft bypivoted connections and secured Y to rotate with said shaft, the centerlines of said connections each being capable of a tangential relation to.a cylinder of suitable size concentric with said shaft, andcontrollable means to adjust said auxiliary blades about said pivotedconnections while in use.

15. In a propeller, a shaft, variable pitch main propeller bladesattached to said shaft, auxiliary.

propeller blades forward of the main blades, said auxiliary blades beingattached to said shaft by pivoted connections, the center lines of saidpivoted connections being capable of a tangential relation to a cylinderparallel to said shaft, and controllable means to adjust said auxiliaryblades about said pivoted connections while said auxiliary blades are inuse.

16. In a propeller, a shaft, variable pitch main propeller bladesattached to said shaft, auxiliary propeller blades forward of the mainblades, said blades being attached to said shaft by pivoted connections,the center lines of said pivoted connections each being capable of atangential relation to a cylinder concentric to said shaft, controllabledirect acting means to vary the pitch of said main propeller blades, andcontrollable means to adjust saidauxiliary blades about said pivotedconnections while said auxiliary blades are in use.

HERBERT L. ADAMS.

